/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.web.reactive.socket.adapter;

import io.netty.handler.codec.http.websocketx.WebSocketFrame;
import org.reactivestreams.Publisher;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import reactor.netty.NettyInbound;
import reactor.netty.NettyOutbound;
import reactor.netty.http.websocket.WebsocketInbound;
import reactor.netty.http.websocket.WebsocketOutbound;

import org.springframework.core.io.buffer.NettyDataBufferFactory;
import org.springframework.web.reactive.socket.CloseStatus;
import org.springframework.web.reactive.socket.HandshakeInfo;
import org.springframework.web.reactive.socket.WebSocketMessage;
import org.springframework.web.reactive.socket.WebSocketSession;


/**
 * {@link WebSocketSession} implementation for use with the Reactor Netty's
 * {@link NettyInbound} and {@link NettyOutbound}.
 *
 * @author Rossen Stoyanchev
 * @since 5.0
 */
public class ReactorNettyWebSocketSession
        extends NettyWebSocketSessionSupport<ReactorNettyWebSocketSession.WebSocketConnection> {

    private final int maxFramePayloadLength;


    /**
     * Constructor for the session, using the {@link #DEFAULT_FRAME_MAX_SIZE} value.
     */
    public ReactorNettyWebSocketSession(WebsocketInbound inbound, WebsocketOutbound outbound,
                                        HandshakeInfo info, NettyDataBufferFactory bufferFactory) {

        this(inbound, outbound, info, bufferFactory, DEFAULT_FRAME_MAX_SIZE);
    }

    /**
     * Constructor with an additional maxFramePayloadLength argument.
     *
     * @since 5.1
     */
    public ReactorNettyWebSocketSession(WebsocketInbound inbound, WebsocketOutbound outbound,
                                        HandshakeInfo info, NettyDataBufferFactory bufferFactory,
                                        int maxFramePayloadLength) {

        super(new WebSocketConnection(inbound, outbound), info, bufferFactory);
        this.maxFramePayloadLength = maxFramePayloadLength;
    }


    @Override
    public Flux<WebSocketMessage> receive() {
        return getDelegate().getInbound()
                .aggregateFrames(this.maxFramePayloadLength)
                .receiveFrames()
                .map(super::toMessage)
                .doOnNext(message -> {
                    if (logger.isTraceEnabled()) {
                        logger.trace(getLogPrefix() + "Received " + message);
                    }
                });
    }

    @Override
    public Mono<Void> send(Publisher<WebSocketMessage> messages) {
        Flux<WebSocketFrame> frames = Flux.from(messages)
                .doOnNext(message -> {
                    if (logger.isTraceEnabled()) {
                        logger.trace(getLogPrefix() + "Sending " + message);
                    }
                })
                .map(this::toFrame);
        return getDelegate().getOutbound()
                .sendObject(frames)
                .then();
    }

    @Override
    public Mono<Void> close(CloseStatus status) {
        return getDelegate().getOutbound().sendClose(status.getCode(), status.getReason());
    }


    /**
     * Simple container for {@link NettyInbound} and {@link NettyOutbound}.
     */
    public static class WebSocketConnection {

        private final WebsocketInbound inbound;

        private final WebsocketOutbound outbound;


        public WebSocketConnection(WebsocketInbound inbound, WebsocketOutbound outbound) {
            this.inbound = inbound;
            this.outbound = outbound;
        }

        public WebsocketInbound getInbound() {
            return this.inbound;
        }

        public WebsocketOutbound getOutbound() {
            return this.outbound;
        }
    }

}
